When an element such as a semiconductor, a resistance and/or a condenser to a substrate is to be bonded or sealed to a substrate, they are bonded together with use of an insulating adhesive or an electroconductive adhesive between the substrate and the element. When the adhesive layer is press worked, the adhesive runs over so that a bonding capacity of the insulating layer or the electroconductive layer formed decreases to deteriorate the performance.
The present applicant proposed an apparatus for hot pressing a thin plate-like workpiece to be used in covering, with a protective sheet made of a thermosetting adhesive, a package substrate in which a thin element such as a semiconductor, a condenser or a resistance is fixed to a predetermined position of a thin plate-like substrate.
See Patent Document 1.
The present inventors examined whether a bonding agent could be prevented from running over in case of bonding or sealing the element onto the substrate by using a hot pressing apparatus shown in FIG. 6(a) with an adhesive. As shown in FIG. 6(b), a bottom face of a lower end of an upper frame member is brought into contact with an upper face of an upper end of a lower frame member by using this apparatus, a lower face of a heat-resistant stretchable film member is brought into contact with upper faces of a substrate on a lower mold member and an element thereon, a workpiece is preliminarily heated with an upper heater plate and a lower heater plate, while the heat-resistant stretchable film member is substantially horizontally held in the state that the film member is prevented from hanging down; the element is sealed onto the substrate with the heat-resistant stretchable film member by pressurizing a heat medium inside a heat medium-filled space, while the heat-resistant stretchable film member is being prevented from stretching outwardly in radial directions. However, contrary to the expectation, it was difficult to well bond or seal the element onto the substrate, while the runout of the adhesive was minimized. In addition, when the element is sealingly bonded to the substrate having the element preliminarily fixedly bonded thereto by using the sealing sheet, it was difficult to make the sealing and the bonding in a uniform thickness, so that a sealed corner was broken or poor sealing occurs.